You can't charge a 505 off a USB wall charger. You can use either the USB computer connection, or a wall charger that plugs into the round charging port on the 505. I happen to have the actual Sony one, but I've heard here on MR that the ones sold for the PSP handheld game console will work. The Sony charger is rated at 2000mA (yeah, 2 amps) -- the 505 must be a hungry little critter. On the plus side, the wall charger charges it very quickly.

I concur with the above. In the early days, I used my phone wall plug to try to charge my reader (usb wall plug). Drained it dry. Thought I killed it. Definitely go with sony or psp charger for wall charger.

Round Plug, Round Plug, Round Plug. That's all you need to remember about reader chargers. As long as the voltage of the round plug charger is correct, it will charge the Sony reader. It doesn't matter if the voltage source is a USB car adapter, a USB wall charger, or a cube type wall charger (Sony or PSP type). I actually use a surplus Dell Axim charger. Of course, you must use a cable with a round plug on one end and a USB A plug on the other with the USB wall charger, or USB car adapter. I have a "y" type cable with both round and USB mini plugs on the reader end.
Just don't expect a charge cable, with a mini USB plug on one end and a USB A plug on the other, to charge the reader unless it is connected to a PC, and then only if the PC is active, i.e. not in standby/sleep mode/hibernation/off.
Charging via PC USB ports is generally slower than charging from a round plug equipped wall charger. That's because the wall chargers usually have more current and/or voltage available than the typical USB port.

Thanks all. I found this and more by simply waking up and trying the search. oops.

It's too bad that sony is trying to make me lug around another brick. I'm definitely going to start a search for a cable that I can plug into my USB charger (one with a round tip). It will be nice to have one brick and a couple of cables to charge my bberry, reader, and ipad.

Like MSJim, I use the "Y" cable. We got ours with a PSP kit. I have also found that this can be used with some types of "battery extenders" - mini battery packs. Maplin (UK) do one comes with many connectors (not a sony so you will still need the "Y"), this has some circuit in it and have found it will charge just about anything - including the 505. Great for holidays as it works with most of my toys.